Hello. Thanks for the review.

>> +      int colors = tgetnum ((char *)"Co");
> I wonder if that cast is really needed any longer.

On my machine with Ubuntu 22.04 and libncurses-dev 6.3 there is no need 
to cast because of const char * in the signature of tgetnum.

But in many manuals on the Internet the signature is described as 
tgetnum(char *).

Since I can't test it on every supported OS with every curses 
implementation I would leave this cast as everywhere in the gdb sources.